الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The ultimate goal of antepartum fetal surveillance is to prevent fetal death and improve perinatal morbidity. The efficacy of umbilical Doppler velocimetry and U/S derived measurements were compared. The Doppler velocimetry detects any change in blood flow impedance in different fetal vessels.
During a normal pregnancy, vascular adaptive changes occurring in the maternal placental bed vessels are necessary to enable them to deliver 500 ml of blood/mm. into the intervillous space (Brosens et al., 1967).
The cytotrophoblast invades the media of the spiral arterioles, a process completed sometimes between the 14th and the 20th week gestation, resulting in the conversion of the muscular spiral arteries into thin—walled, flaccid uteroplacental vessels which progressively dilate and loose their vasomotor tone, this is vital for adequate placentation and a normal uteroplacental blood flow (Robertson et al., 1975).